Portable telephones have a plurality of input keys arranged on the surface of a main body case, and the surface of each of the input keys has printed thereon a key identification symbol, such as a numeral, character, and the like (hereafter referred to merely as a “character”). When such input keys are depressed, characters can be input. Portable telephones are also known wherein in view of the manipulability of input keys in the nighttime, the bodies of the input keys of light transmitting resin are each provided with a light blocking film formed by coating and partly cut out to provide a light transmitting pattern in the form of a character, and the input keys are illuminated from below with LEDs in the nighttime.
However, portable telephones wherein the input keys are illuminated from below have the problem of being undesirable in design because when the LEDs are off, the structure in the rear of the key body can be seen through the body which is transparent. To overcome this problem, it appears useful to make the key bodies from a semitransparent resin, but light is then transmitted through the key bodies in a reduced amount, giving rise to the problem that the characters are not readily visible in the nighttime.